1. Field of the Invention
The present invention relates to a power semiconductor device, and more particularly to a technique of connecting switching elements in parallel which are sealed with resin by the transfer mold process and the like in a power control device and the like.
2. Description of the Background Art
In general, a power semiconductor element including one switching element (a MOS-FET, a bipolar transistor, an IGBT and the like) which is sealed with resin by the transfer mold process and the like is termed a 1 in 1 type power module. A power conversion device, typically a conventional inverter or converter having the 1 in 1 type power module and a control circuit thereof within, has presented the following problem: namely, a semiconductor substrate and the like included in the control circuit is subjected to strong noise and electromagnetic waves generated by a wiring inductance at the time of switching of the switching element, resulting in a malfunction or a breakdown of the power conversion device.
Another problem with the conventional power conversion device is an increase in the overall packaging area because of a wiring bus bar mounted outside the sealing resin.
Japanese Patent Application Laid-Open No. 11-299239 (1999), 2000-023462 and 10-209197 (1998) give examples of power conversion devices so designed in length, shape and the like of a wiring that they reduce the wiring inductance.
The structures of the above power conversion devices are not necessarily premised on the use of the 1 in 1 type power module as a power module. Those are thus less-than-optimal structures when they are premised on the use of the 1 in 1 type power module, leaving problems from the viewpoints of wiring inductance, packaging area and the like.